Choosing which properties of the data to use as input to multivariate decision algorithms -- a.k.a. feature selection -- is an important step in solving any problem with machine learning. While there is a clear trend towards training sophisticated deep networks on large numbers of relatively unprocessed inputs (so-called automated feature engineering), for many tasks in physics, sets of theoretically well-motivated and well-understood features already exist. Working with such features can bring many benefits, including greater interpretability, reduced training and run time, and enhanced stability and robustness. We develop a new feature selection method based on Distance Correlation (DisCo), and demonstrate its effectiveness on the tasks of boosted top- and $W$-tagging. Using our method to select features from a set of over 7,000 energy flow polynomials, we show that we can match the performance of much deeper architectures, by using only ten features and two orders-of-magnitude fewer model parameters.
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鉴于HEP研究的核心,数据科学(DS)和机器学习(ML)在高能量物理学(HEP)中的作用增长良好和相关。此外,利用物理数据固有的对称性激发了物理信息的ML作为计算机科学研究的充满活力的子场。 HEP研究人员从广泛使用的材料中受益匪浅,可用于教育,培训和劳动力开发。他们还为这些材料做出了贡献,并为DS/ML相关的字段提供软件。物理部门越来越多地在DS,ML和物理学的交集上提供课程,通常使用HEP研究人员开发的课程,并涉及HEP中使用的开放软件和数据。在这份白皮书中,我们探讨了HEP研究与DS/ML教育之间的协同作用,讨论了此交叉路口的机会和挑战,并提出了将是互惠互利的社区活动。
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机器学习在加强和加速寻求新基本物理学方面发挥着至关重要的作用。我们审查了新物理学的机器学习方法和应用中,在地面高能量物理实验的背景下,包括大型强子撞机,罕见的事件搜索和中微生实验。虽然机器学习在这些领域拥有悠久的历史,但深入学习革命(2010年代初)就研究的范围和雄心而产生了定性转变。这些现代化的机器学习发展是本综述的重点。
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The ability to convert reciprocating, i.e., alternating, actuation into rotary motion using linkages is hindered fundamentally by their poor torque transmission capability around kinematic singularity configurations. Here, we harness the elastic potential energy of a linear spring attached to the coupler link of four-bar mechanisms to manipulate force transmission around the kinematic singularities. We developed a theoretical model to explore the parameter space for proper force transmission in slider-crank and rocker-crank four-bar kinematics. Finally, we verified the proposed model and methodology by building and testing a macro-scale prototype of a slider-crank mechanism. We expect this approach to enable the development of small-scale rotary engines and robotic devices with closed kinematic chains dealing with serial kinematic singularities, such as linkages and parallel manipulators.
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Neural network (NN) potentials promise highly accurate molecular dynamics (MD) simulations within the computational complexity of classical MD force fields. However, when applied outside their training domain, NN potential predictions can be inaccurate, increasing the need for Uncertainty Quantification (UQ). Bayesian modeling provides the mathematical framework for UQ, but classical Bayesian methods based on Markov chain Monte Carlo (MCMC) are computationally intractable for NN potentials. By training graph NN potentials for coarse-grained systems of liquid water and alanine dipeptide, we demonstrate here that scalable Bayesian UQ via stochastic gradient MCMC (SG-MCMC) yields reliable uncertainty estimates for MD observables. We show that cold posteriors can reduce the required training data size and that for reliable UQ, multiple Markov chains are needed. Additionally, we find that SG-MCMC and the Deep Ensemble method achieve comparable results, despite shorter training and less hyperparameter tuning of the latter. We show that both methods can capture aleatoric and epistemic uncertainty reliably, but not systematic uncertainty, which needs to be minimized by adequate modeling to obtain accurate credible intervals for MD observables. Our results represent a step towards accurate UQ that is of vital importance for trustworthy NN potential-based MD simulations required for decision-making in practice.
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Fake news detection has become a research area that goes way beyond a purely academic interest as it has direct implications on our society as a whole. Recent advances have primarily focused on textbased approaches. However, it has become clear that to be effective one needs to incorporate additional, contextual information such as spreading behaviour of news articles and user interaction patterns on social media. We propose to construct heterogeneous social context graphs around news articles and reformulate the problem as a graph classification task. Exploring the incorporation of different types of information (to get an idea as to what level of social context is most effective) and using different graph neural network architectures indicates that this approach is highly effective with robust results on a common benchmark dataset.
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深度学习算法的最新进展为解决许多医学图像分析问题带来了重大好处。培训深度学习模型通常需要具有专家标记注释的大型数据集。但是,获取专家标记的注释不仅昂贵,而且主观,容易出错,并且观察者内部变异性会引入标签。由于解剖学的模棱两可,使用深度学习模型来细分医学图像时,这尤其是一个问题。基于图像的医学诊断工具使用经过不正确分段标签训练的深度学习模型可以导致错误的诊断和治疗建议。与单评论注释相比,多评价者注释可能更适合于使用小型培训集的深度学习模型进行训练。本文的目的是开发和评估一种基于MRI中病变特征的多评价者注释和解剖学知识来生成概率标签的方法,以及一种使用概率的标签使用归一化活动性损失作为A的病变特征的解剖学知识,以训练分割模型”。耐噪声损失的功能。通过将17个膝盖MRI扫描的二进制基础真理进行比较,以评估该模型,以用于临床分割和检测骨髓病变(BML)。该方法与二进制跨透镜损失函数相比,该方法成功提高了精度14,召回22和骰子得分8%。总体而言,这项工作的结果表明,使用软标签的拟议归一化主动损失成功地减轻了嘈杂标签的影响。
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标准化流是可易处理的密度模型,可以近似复杂的目标分布,例如物理系统的玻尔兹曼分布。但是,当前的训练流量要么具有寻求模式的行为,要么使用昂贵的MCMC模拟事先生成的目标样本,要么使用具有很高差异的随机损失。为了避免这些问题,我们以退火重要性采样(AIS)增强流量,并最大程度地减少覆盖$ \ alpha $ -divergence的质量,并使用$ \ alpha = 2 $,从而最大程度地减少了重要性的重量差异。我们的方法是流动性Bootstrap(Fab),使用AIS在流动较差的目标区域中生成样品,从而促进了新模式的发现。我们以AIS的最小差异分布来定位,以通过重要性抽样来估计$ \ alpha $ -Divergence。我们还使用优先的缓冲区来存储和重复使用AIS样本。这两个功能显着提高了Fab的性能。我们将FAB应用于复杂的多模式目标,并表明我们可以在以前的方法失败的情况下非常准确地近似它们。据我们所知,我们是第一个仅使用非均衡目标密度学习丙氨酸二肽分子的玻璃体分布,而无需通过分子动力学(MD)模拟生成的样品:FAB与通过最大可能性训练更好的效果,而不是通过最大可能性产生的结果。在MD样品上使用100倍的目标评估。在重新获得重要权重的样品后,我们获得了与地面真相几乎相同的二面角的无偏直方图。
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低压网络中分布式能源的渗透不断增加,这将最终用户从消费者转变为生产者。但是,由于零售和网络服务提供的监管分离,智能电表数据的不完整智能电表的推出和缺乏智能电表数据,这使主动分配网络管理变得困难。此外,分销网络运营商通常无法访问实时智能电表数据,这会带来额外的挑战。由于缺乏更好的解决方案,他们使用毯子屋顶太阳能出口限制,从而导致次优结果。为了解决这个问题,我们设计了一个有条件的生成对抗网络(CGAN)的模型来预测家庭太阳能产生和电力需求,这是用于在不确定性下用于计算公平操作信封的机会约束最佳功率流的输入。
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在过去的几十年中,机器学习已应用于几乎所有计算机科学领域。引入gan允许在医学研究和文本预测领域中产生新的可能性。但是,这些新领域与对隐私敏感的数据有效。为了维护用户隐私,可以使用联合学习,差异隐私和gans的组合来处理私人数据,而无需赠送用户的隐私。最近,已经发布了两种此类组合的实现:DP-FED-AVG GAN和GS-WGAN。本文比较了它们的性能,并引入了DP-FED-FED-AVG GAN的替代版本,该版本利用Denoisising技术来抵抗准确性的损失,而准确性损失通常在应用差异隐私和联合学习到GAN时通常会发生。我们还比较了DENOCED DP-FED-AVG GAN的新颖适应性与该领域最新的实现。
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